It's possible for a key to contain whitespace in its name. This breaks the external special remote protocol, which uses whitespace to separate the key parameter from subsequent parameters.

I think that this only causes problems for WORM keys. --Joey

Ok, went with my last approach, rather than complicating all special remotes due to this problem, we'll deprecate WORM keys with spaces in their name, and provide a migratipon path.

The error message looks like this:

Sorry, this file cannot be stored on an external special remote because its key's name contains a space. To avoid this problem, you can run: git-annex migrate --backend=WORM

This is fixed as well as is feasible, so while that kind of sucks, calling it done. --Joey